Abstract
Obesity is closely associated with oxidative stress and chronic inflammation leading to related metabolic diseases. Some natural extracts or polyphenols reportedly possess anti-obesity and anti-inflammatory effects as well as antioxidant activity. In this study, we assessed the correlations between the antioxidant, anti-obesity, and anti-inflammatory activities of plant extracts with potent antioxidant activity in diet-induced obese mice. Sprouts of Cedrela sinensis (CS) and Oenothera biennis L. (OB) were selected as the most potent antioxidant plant based on analysis of in vitro antioxidant activity of the extracts of ten different edible plants. C57BL/6 mice were fed with a high-fat diet (HFD) and orally treated with 50% ethanol extract of CS or OB at 50 or 100 mg/kg body weight 5 days a week for 14 weeks. Body weight gain, weight of adipose tissue, adipocyte size, and levels of lipid metabolism, inflammation, and oxidative stress markers were investigated. The CS or OB extract reduced body weight gain, visceral adipose tissue weight, adipocyte size, and plasma leptin levels, and expressions of adipogenic genes (PPARγ and fatty acid synthase) in the adipose tissue and liver of HFD-fed mice. Both extracts also reduced mRNA levels of pro-inflammatory cytokines (IL-6 and TNF-α) and oxidative stress-related genes (heme oxygenase- (HO-) 1 and p40phox). Body weight gain of mice was significantly correlated with visceral adipose tissue weight and adipocyte size. Body weight gain and adipocyte size were significantly correlated with plasma total cholesterol and 8-epi PGF2α levels, mRNA levels of leptin, HO-1, p40phox, and CD-11 in the adipose tissue, and mRNA levels of TNF-α in the adipose tissue and liver. These results suggest that the CS and OB extracts with potent antioxidant activity may inhibit fat deposition in adipose tissue and subsequent inflammation.
Highlights
Obesity increases the risk of various metabolic diseases including type-2 diabetes, hypertension, fatty liver, and cardiovascular diseases
Data on the in vitro antioxidant activity and extraction yield of the extracts are summarized in Table 2. e Oenothera biennis L. (OB) extract showed the highest diphenyl-1 picrylhydrazyl (DPPH) radical scavenging activity, followed by the Cedrela sinensis (CS) extract. e OB extract showed the highest ferric reducing antioxidant power (FRAP), followed by the extracts of Acanthopanax koreanum (AK) and CS. ese results indicated the potent antioxidant activities of the OB and CS extracts
At 14 weeks, body weight gains of the HFD control (HFC) group were increased approximately 2.3-fold compared with those of the LFD control (LFC) group. e average body weight gains of the Lycopene beadlets (LY), CS-L, CS-H, OB-L, and OB-H groups were reduced by 28.8%, 27.7%, 43.5%, 44.6%, and 46.7%, respectively, compared to the weight gains of the HFC group. ese results indicate that supplementation with the CS and OB extracts, especially OB, reduced the body weight gains more effectively than LY treatment (Table 3)
Summary
Obesity increases the risk of various metabolic diseases including type-2 diabetes, hypertension, fatty liver, and cardiovascular diseases. Obesity-induced oxidative stress and inflammation may cause the development of obesityassociated metabolic diseases [1]. High fat consumption leads to hyperlipidemia and subsequent increase of fatty acid oxidation and cellular reactive oxygen species (ROS), which activates the nuclear factor kappa beta (NF-κB) pathway and increases the secretion of pro-inflammatory cytokines in various tissues [2, 3]. Excessive ROS induce oxidative damage of DNA, lipids, and proteins in cells, thereby leading to various diseases [4, 5]. Chronic and sterile low-grade inflammation is frequently observed in the adipose tissue, liver, and kidneys of obese humans and rodents [6, 7].
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